1. Field of the Invention
This invention relates to a ceramic which can be utilized as the electronic material such as dielectric porcelain substrate, etc. and a circuit substrate and an electronic circuit substrate by use of the ceramic, and also a process for producing the ceramic.
2. Related Background Art
In the prior art, an electronic circuit substrate has been constituted by providing only a conductor circuit, a conductor circuit and a resistance, or a conductor circuit, a resistance and a capacitor within the limited range, and other functional portions mounted as the device as separated from the substrate.
More specifically, for example, as a porcelain substrate of the prior art, a substrate primarily having a conductor and a resistor built therein was used, and a capacitor gas mounted by soldering thereon as a chip member, etc. For this reason, miniaturization of electronic circuit has been limited. FIG. 1 shows an example thereof, in which 111 is a porcelain substrate, 112 a conductor circuit, 113 a resistor and 114 a chip capacitor.
In recent years, attempts have been made to have a plurality of capacitors built in within a substrate by varying the dielectric constants within the same porcelain substrate.
However, in the prior art, it has been very difficult to practice a method for forming different dielectric portions within the same substrate. For example, as is self-explanatory when considering cumbersomeness in preparing a laminated ceramic capacitor, a substrate having a plurality of capacitors built therein has not yet been realized or practically applied under the present situation. It has also been a technical task to make portions with high dielectric constants sufficiently separated as the device functional portions to the extent that no influence may be exerted on each other in actuation within the limited structural space.
Further, such problem of building in separately the functional portions concerned with electronic parts or circuit substrates are not limited to dielectric porcelains, but has revealed itself generally in the case of forming two or more of the same kind or different kinds of functional portions within the ceramic.